From a hospital-based surveillance carried out in Rajendra Memorial Research Institute of Medical Sciences, Patna, Bihar, India, the socio-economic, demographic and treatment response information of 737 patients admitted with visceral leishmaniasis (VL) during January 2001-December 2003, were analysed. The disease was two times higher in males than in females because of several factors including clothing pattern, sleeping habits and occupation. In Bihar, the second poorest state in India, poverty plays a major role in perpetuation of the disease, contributing to malnutrition, illiteracy (60%), and poor housing (82%). Further, presences of peri-domestic animal shelters around houses (63%) and vegetations (77%) facilitate breeding of sand fly vector. Clinical and laboratory characteristics were similar in the age groups <12 years and >12 years. The increasing unresponsiveness of VL patients to conventional anti-leishmanial drugs, e.g. sodium antimony gluconate (SAG) and pentamidine, has definitely posed a major therapeutic challenge in combating the disease. Amphotericin B, though costly, is highly effective. Miltefosine is a highly promising new oral drug for VL.